This invention relates to a semiconductor integrated circuit device, and more particularly to a semiconductor actuator utilizing an electromagnetic force, or a semiconductor sensor utilizing an electromagnetic induction.
Recently, with development of Compact Disks (CDs) of digital audio disks, Laservision Disks (LVDs) of video and acoustic information media, write once Read Many-type optical disks, and rewritable photomagnetic disks, etc., it has been required for an optical pickup to be small-sized and lighten weight. To neet such a requirement, in place of an optical pickup of a structure such that optical parts such as lens or mirror, etc. are combined with each other, an optical integrated circuit type pickup to which the integrated circuit technology established in the manufacturing field of LSI is applied has been proposed. For example, see Toshiaki Suhara, Shogo Ura, and Hiroshi Nishihara (Department of Electronics, Osaka University), `Optical Integrated Disk Pickup Head`, "Optronics" monthly published, No. 2, pp. 149-154 (1989), or the publication of the Japanese Patent Laid Open Publication No. 296540/86.
However, in case that the above-mentioned optical integrated type pickup is used in an actual playback equipment such as a CD player or an LVD player, etc., it is required to affix or mount an actuator for control. In this case, following the conventional form, an optical head of a structure which will be described below will be provided. This optical head is composed of, e.g., a cylindrical magnet, a cylindrical bobbin, and a semiconductor chip on which an optical integrated circuit-type pickup is formed. The cylindrical bobbin is of a hollow structure in which the diameter of the hollow portion is larger than that of the cylindrical magnet. This cylindrical magnet is mounted on the cylindrical bobbin so that it is seated thereon. One end surface of the cylindrical bobbin is closed and the semiconductor chip is affixed on that end surface. Further, an electromagnetic coil is provided on the cylindrical side surface of the cylindrical bobbin so as to surround it. In this case, a magnetic field is formed by magnetic lines of force directed from one end surface of the cylindrical magnet toward the other end surface thereof. These magnetic lines of force penetrate through the end surface of the bobbin and the semiconductor chip surface. When a current is caused to flow in the electromagnetic coil on the side surface of the bobbin, an electromagnetic force attempting to move the electromagnetic coil, i.e., the bobbin toward either a positive or a negative direction of the longitudinal axis of the cylindrical magnet is produced by "Fleming's left-hand rule" Accordingly, since the amount of movement of the semiconductor chip in the axial direction of the magnet can be adjusted by changing the direction of current flowing and the intensity of that current, this mechanism will form a focusing actuator.
However, since the sizes of these electromagnetic coil and magnet are considerably larger than that of the semiconductor chip, there was a problem in that the relatively small size of semiconductor chip was not taken advantage of. In addition, because of the large number of parts, there was room for improvement from the viewpoint of assembly and cost.
An object of this invention is to provide a semiconductor integrated circuit device which can be utilized as a small-sized and lightweight actuator or a small-sized sensor.